Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp

Index: third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
index 020e539047db244fcc9878bc8f9e5da1fe0beefa..d162337bd930b9e79f47b8ffb29dce60a7d43e64 100644
--- a/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/BaseAudioContext.cpp
@@ -44,6 +44,7 @@
 #include "modules/webaudio/AudioBufferCallback.h"
 #include "modules/webaudio/AudioBufferSourceNode.h"
 #include "modules/webaudio/AudioContext.h"
+#include "modules/webaudio/AudioContextOptions.h"
 #include "modules/webaudio/AudioListener.h"
 #include "modules/webaudio/AudioNodeInput.h"
 #include "modules/webaudio/AudioNodeOutput.h"
@@ -75,20 +76,24 @@
 #include "platform/UserGestureIndicator.h"
 #include "platform/audio/IIRFilter.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebAudioLatencyHint.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
-BaseAudioContext* BaseAudioContext::create(Document& document,
-                                           ExceptionState& exceptionState) {
-  return AudioContext::create(document, exceptionState);
+BaseAudioContext* BaseAudioContext::create(
+    Document& document,
+    const WebAudioLatencyHint& latencyHint,
+    ExceptionState& exceptionState) {
+  return AudioContext::create(document, latencyHint, exceptionState);
 }
 
 // FIXME(dominicc): Devolve these constructors to AudioContext
 // and OfflineAudioContext respectively.
 
 // Constructor for rendering to the audio hardware.
-BaseAudioContext::BaseAudioContext(Document* document)
+BaseAudioContext::BaseAudioContext(Document* document,
+                                   const WebAudioLatencyHint& latencyHint)
     : ActiveScriptWrappable(this),
       ActiveDOMObject(document),
       m_destinationNode(nullptr),
@@ -112,7 +117,7 @@ BaseAudioContext::BaseAudioContext(Document* document)
     m_userGestureRequired = true;
   }
 
-  m_destinationNode = DefaultAudioDestinationNode::create(this);
+  m_destinationNode = DefaultAudioDestinationNode::create(this, latencyHint);
 
   initialize();
 }
@@ -590,6 +595,10 @@ String BaseAudioContext::state() const {
   return "";
 }
 
+double BaseAudioContext::baseLatency() const {
+  return framesPerBuffer() * 2 / sampleRate();

[Raymond Toy, 2016/11/30 21:50:27]

Cast sampleRate() to double so that we get double arithmetic here.

[Andrew MacPherson, 2016/12/01 12:11:56]

Done.

+}
+
 void BaseAudioContext::setContextState(AudioContextState newState) {
   DCHECK(isMainThread());